1. Field
The present embodiments relate to batteries for portable electronic devices. More specifically, the present embodiments relate to in-situ battery health detectors and end-of-life-indicators within portable electronic devices.
2. Related Art
Portable electronic devices, such as laptop computers, portable media players, and/or mobile phones, typically operate using a battery. Furthermore, high-energy battery designs for portable devices often include battery packs that contain battery cells connected together in various series and parallel configurations. For example, a six-cell battery pack of lithium cells may be configured in a three in series, two in parallel (3s2p) configuration. If a single cell can provide a maximum of 3 amps with a voltage ranging from 2.7 volts to 4.2 volts, then the battery pack may have a voltage range of 8.1 volts to 12.6 volts and provide 6 amps of current. The charge in such batteries may be managed by a circuit board, which is commonly known as a protection circuit module (PCM) and/or battery management unit (BMU).
However, once a battery is created, the battery's capacity may diminish over time from use, age, lack of maintenance, damage, and/or manufacturing defects. For example, oxidation of electrolyte and/or degradation of cathode and anode material within a battery may be caused by repeated charge cycles and/or age, which in turn may cause a gradual reduction in the battery's capacity. As the battery continues to age and degrade, the capacity's rate of reduction may increase. Once the battery reaches 80% of initial capacity, the battery's useful life may be expended.
Subsequent use of a battery beyond the battery's end-of-life may cause swelling of the battery's cells and may potentially damage the device powered by the battery, while providing little charge to the device. However, conventional battery-monitoring mechanisms may only provide a rough estimate of the battery's state-of-charge and may not include functionality to assess the battery's health. As a result, a user of the battery may not be aware of the battery's age and/or degradation and may continue using the battery beyond the battery's end-of-life.
Hence, what is needed is a mechanism for assessing battery health and end-of-life and managing battery use based on the assessed health.